AWS issues with 172.0.0.0/12

Fri Oct 11 11:48:34 UTC 2019

I'm surprised that no one else has corrected this, so allow me to do
so for the record.

No, Mehmet's public IP was _not_ from the RFC 1918 172.16.0.0/16
range. 

One of the public ipv4 ranges that AT&T assigns subscriber addresses
from is 172.0.0.0/12: [ 172.0.0.0 - 172.15.255.255 ]

 https://whois.arin.net/rest/net/NET-172-0-0-0-1

One of the private ipv4 ranges set aside by RFC 1918 is the
neighboring 172.16.0.0/12: [ 172.16.0.0 - 172.31.255.255 ]

 https://whois.arin.net/rest/net/NET-172-16-0-0-1

We notice more mis-originations of our 172.0.0.0/12 space and its
more-specifics than any of our other ipv4 blocks, probably because
other folks are similarly confused.  So please, if you intend to use
RFC1918 space, please check your filters to make sure you're using
172.16.0.0/12 and not our 172.0.0.0/12.

						Jay B.

Mehmet Akcin writes:
 > Yes
 > 
 > On Wed, Oct 9, 2019 at 20:46 Javier J <javier at advancedmachines.us> wrote:
 > 
 > > I'm just curious, was the ip in the RFC 1918 172.16.0.0/16 range?
 > >
 > > https://tools.ietf.org/html/rfc1918
 > >
 > >
 > >
 > > On Mon, Oct 7, 2019 at 6:01 PM Mehmet Akcin <mehmet at akcin.net> wrote:
 > >
 > >> To close the loop here (in case if someone has this type of issue in the
 > >> future), I have spoken to AT&T instead of trying to work it out with AWS
 > >> Hosted Vendor, Reolink.
 > >>
 > >> AT&T Changed my public IP, and now I am no longer in that 172.x.x.x
 > >> block, everything is working fine.
 > >>
 > >> mehmet
 > >>
 > >> On Thu, Oct 3, 2019 at 2:54 PM Javier J <javier at advancedmachines.us>
 > >> wrote:
 > >>
 > >>> Auto generated VPC in AWS use RFC1819 addresses. This should not
 > >>> interfere with pub up space.
 > >>>
 > >>> What is the exact issue? If you can't ping something in AWS chances are
 > >>> it's a security group blocking you.
 > >>>
 > >>>
 > >>>
 > >>> On Tue, Oct 1, 2019, 7:00 PM Jim Popovitch via NANOG <nanog at nanog.org>
 > >>> wrote:
 > >>>
 > >>>> On October 1, 2019 9:39:03 PM UTC, Matt Palmer <mpalmer at hezmatt.org>
 > >>>> wrote:
 > >>>> >On Tue, Oct 01, 2019 at 04:50:33AM -0400, Jim Popovitch via NANOG
 > >>>> >wrote:
 > >>>> >> On 10/1/2019 4:09 AM, Christopher Morrow wrote:
 > >>>> >> > possible that this is various AWS customers making
 > >>>> >iptables/firewall mistakes?
 > >>>> >> >    "block that pesky rfc1918 172/12 space!!"
 > >>>> >>
 > >>>> >> AWS also uses some 172/12 space on their internal network (e.g. the
 > >>>> >network
 > >>>> >> that sits between EC2 instances and the AWS external firewalls)
 > >>>> >
 > >>>> >Does AWS use 172.0.0.0/12 internally, or 172.16.0.0/12?  They're
 > >>>> >different
 > >>>> >things, after all.
 > >>>> >
 > >>>>
 > >>>> I don't know their entire operations, but they do use some
 > >>>> 172.16.0.0/12
 > >>>> addresses internally. And yes, that is very different than 172/12, sorry
 > >>>> for the confusion.
 > >>>>
 > >>>> -Jim P.
 > >>>>
 > >>>> --
 > Mehmet
 > +1-424-298-1903